xref: /linux/drivers/iio/light/ltrf216a.c (revision df822f2e36cf2c2864d166d90cf002df4d8689e5) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * LTRF216A Ambient Light Sensor
4  *
5  * Copyright (C) 2022 Collabora, Ltd.
6  * Author: Shreeya Patel <shreeya.patel@collabora.com>
7  *
8  * Copyright (C) 2021 Lite-On Technology Corp (Singapore)
9  * Author: Shi Zhigang <Zhigang.Shi@liteon.com>
10  *
11  * IIO driver for LTRF216A (7-bit I2C slave address 0x53).
12  */
13 
14 #include <linux/bitfield.h>
15 #include <linux/bits.h>
16 #include <linux/delay.h>
17 #include <linux/i2c.h>
18 #include <linux/init.h>
19 #include <linux/iopoll.h>
20 #include <linux/module.h>
21 #include <linux/mutex.h>
22 #include <linux/pm.h>
23 #include <linux/pm_runtime.h>
24 #include <linux/regmap.h>
25 
26 #include <linux/iio/iio.h>
27 
28 #include <linux/unaligned.h>
29 
30 #define LTRF216A_ALS_RESET_MASK		BIT(4)
31 #define LTRF216A_ALS_DATA_STATUS	BIT(3)
32 #define LTRF216A_ALS_ENABLE_MASK	BIT(1)
33 #define LTRF216A_MAIN_CTRL		0x00
34 #define LTRF216A_ALS_MEAS_RES		0x04
35 #define LTRF216A_ALS_GAIN		0x05
36 #define LTRF216A_PART_ID		0x06
37 #define LTRF216A_MAIN_STATUS		0x07
38 #define LTRF216A_ALS_CLEAR_DATA_0	0x0a
39 #define LTRF216A_ALS_CLEAR_DATA_1	0x0b
40 #define LTRF216A_ALS_CLEAR_DATA_2	0x0c
41 #define LTRF216A_ALS_DATA_0		0x0d
42 #define LTRF216A_ALS_DATA_1		0x0e
43 #define LTRF216A_ALS_DATA_2		0x0f
44 #define LTRF216A_INT_CFG		0x19
45 #define LTRF216A_INT_PST		0x1a
46 #define LTRF216A_ALS_THRES_UP_0		0x21
47 #define LTRF216A_ALS_THRES_UP_1		0x22
48 #define LTRF216A_ALS_THRES_UP_2		0x23
49 #define LTRF216A_ALS_THRES_LOW_0	0x24
50 #define LTRF216A_ALS_THRES_LOW_1	0x25
51 #define LTRF216A_ALS_THRES_LOW_2	0x26
52 #define LTRF216A_ALS_READ_DATA_DELAY_US	20000
53 
54 static const int ltrf216a_int_time_available[][2] = {
55 	{ 0, 400000 },
56 	{ 0, 200000 },
57 	{ 0, 100000 },
58 	{ 0,  50000 },
59 	{ 0,  25000 },
60 };
61 
62 static const int ltrf216a_int_time_reg[][2] = {
63 	{ 400, 0x03 },
64 	{ 200, 0x13 },
65 	{ 100, 0x22 },
66 	{  50, 0x31 },
67 	{  25, 0x40 },
68 };
69 
70 struct ltr_chip_info {
71 	/* Chip contains CLEAR_DATA_0/1/2 registers at offset 0xa..0xc */
72 	bool		has_clear_data;
73 	/* Lux calculation multiplier for ALS data */
74 	int		lux_multiplier;
75 };
76 
77 /*
78  * Window Factor is needed when the device is under Window glass
79  * with coated tinted ink. This is to compensate for the light loss
80  * due to the lower transmission rate of the window glass and helps
81  * in calculating lux.
82  */
83 #define LTRF216A_WIN_FAC	1
84 
85 struct ltrf216a_data {
86 	struct regmap *regmap;
87 	struct i2c_client *client;
88 	const struct ltr_chip_info *info;
89 	u32 int_time;
90 	u16 int_time_fac;
91 	u8 als_gain_fac;
92 	/*
93 	 * Protects regmap accesses and makes sure integration time
94 	 * remains constant during the measurement of lux.
95 	 */
96 	struct mutex lock;
97 };
98 
99 static const struct iio_chan_spec ltrf216a_channels[] = {
100 	{
101 		.type = IIO_LIGHT,
102 		.info_mask_separate =
103 			BIT(IIO_CHAN_INFO_RAW) |
104 			BIT(IIO_CHAN_INFO_PROCESSED) |
105 			BIT(IIO_CHAN_INFO_INT_TIME),
106 		.info_mask_separate_available =
107 			BIT(IIO_CHAN_INFO_INT_TIME),
108 	},
109 };
110 
111 static void ltrf216a_reset(struct iio_dev *indio_dev)
112 {
113 	struct ltrf216a_data *data = iio_priv(indio_dev);
114 
115 	/* reset sensor, chip fails to respond to this, so ignore any errors */
116 	regmap_write(data->regmap, LTRF216A_MAIN_CTRL, LTRF216A_ALS_RESET_MASK);
117 
118 	/* reset time */
119 	usleep_range(1000, 2000);
120 }
121 
122 static int ltrf216a_enable(struct iio_dev *indio_dev)
123 {
124 	struct ltrf216a_data *data = iio_priv(indio_dev);
125 	struct device *dev = &data->client->dev;
126 	int ret;
127 
128 	/* enable sensor */
129 	ret = regmap_set_bits(data->regmap,
130 			      LTRF216A_MAIN_CTRL, LTRF216A_ALS_ENABLE_MASK);
131 	if (ret) {
132 		dev_err(dev, "failed to enable sensor: %d\n", ret);
133 		return ret;
134 	}
135 
136 	/* sleep for one integration cycle after enabling the device */
137 	msleep(ltrf216a_int_time_reg[0][0]);
138 
139 	return 0;
140 }
141 
142 static int ltrf216a_disable(struct iio_dev *indio_dev)
143 {
144 	struct ltrf216a_data *data = iio_priv(indio_dev);
145 	struct device *dev = &data->client->dev;
146 	int ret;
147 
148 	ret = regmap_write(data->regmap, LTRF216A_MAIN_CTRL, 0);
149 	if (ret)
150 		dev_err(dev, "failed to disable sensor: %d\n", ret);
151 
152 	return ret;
153 }
154 
155 static void ltrf216a_cleanup(void *data)
156 {
157 	struct iio_dev *indio_dev = data;
158 
159 	ltrf216a_disable(indio_dev);
160 }
161 
162 static int ltrf216a_set_int_time(struct ltrf216a_data *data, int itime)
163 {
164 	struct device *dev = &data->client->dev;
165 	unsigned int i;
166 	u8 reg_val;
167 	int ret;
168 
169 	for (i = 0; i < ARRAY_SIZE(ltrf216a_int_time_available); i++) {
170 		if (ltrf216a_int_time_available[i][1] == itime)
171 			break;
172 	}
173 	if (i == ARRAY_SIZE(ltrf216a_int_time_available))
174 		return -EINVAL;
175 
176 	reg_val = ltrf216a_int_time_reg[i][1];
177 
178 	ret = regmap_write(data->regmap, LTRF216A_ALS_MEAS_RES, reg_val);
179 	if (ret) {
180 		dev_err(dev, "failed to set integration time: %d\n", ret);
181 		return ret;
182 	}
183 
184 	data->int_time_fac = ltrf216a_int_time_reg[i][0];
185 	data->int_time = itime;
186 
187 	return 0;
188 }
189 
190 static int ltrf216a_get_int_time(struct ltrf216a_data *data,
191 				 int *val, int *val2)
192 {
193 	*val = 0;
194 	*val2 = data->int_time;
195 	return IIO_VAL_INT_PLUS_MICRO;
196 }
197 
198 static int ltrf216a_set_power_state(struct ltrf216a_data *data, bool on)
199 {
200 	struct device *dev = &data->client->dev;
201 	int ret = 0;
202 
203 	if (on) {
204 		ret = pm_runtime_resume_and_get(dev);
205 		if (ret) {
206 			dev_err(dev, "failed to resume runtime PM: %d\n", ret);
207 			return ret;
208 		}
209 	} else {
210 		pm_runtime_put_autosuspend(dev);
211 	}
212 
213 	return ret;
214 }
215 
216 static int ltrf216a_read_data(struct ltrf216a_data *data, u8 addr)
217 {
218 	struct device *dev = &data->client->dev;
219 	int ret, val;
220 	u8 buf[3];
221 
222 	ret = regmap_read_poll_timeout(data->regmap, LTRF216A_MAIN_STATUS,
223 				       val, val & LTRF216A_ALS_DATA_STATUS,
224 				       LTRF216A_ALS_READ_DATA_DELAY_US,
225 				       LTRF216A_ALS_READ_DATA_DELAY_US * 50);
226 	if (ret) {
227 		dev_err(dev, "failed to wait for measurement data: %d\n", ret);
228 		return ret;
229 	}
230 
231 	ret = regmap_bulk_read(data->regmap, addr, buf, sizeof(buf));
232 	if (ret) {
233 		dev_err(dev, "failed to read measurement data: %d\n", ret);
234 		return ret;
235 	}
236 
237 	return get_unaligned_le24(&buf[0]);
238 }
239 
240 static int ltrf216a_get_lux(struct ltrf216a_data *data)
241 {
242 	int ret, greendata;
243 	u64 lux;
244 
245 	ret = ltrf216a_set_power_state(data, true);
246 	if (ret)
247 		return ret;
248 
249 	greendata = ltrf216a_read_data(data, LTRF216A_ALS_DATA_0);
250 	if (greendata < 0)
251 		return greendata;
252 
253 	ltrf216a_set_power_state(data, false);
254 
255 	lux = greendata * data->info->lux_multiplier * LTRF216A_WIN_FAC;
256 
257 	return lux;
258 }
259 
260 static int ltrf216a_read_raw(struct iio_dev *indio_dev,
261 			     struct iio_chan_spec const *chan, int *val,
262 			     int *val2, long mask)
263 {
264 	struct ltrf216a_data *data = iio_priv(indio_dev);
265 	int ret;
266 
267 	switch (mask) {
268 	case IIO_CHAN_INFO_RAW:
269 		ret = ltrf216a_set_power_state(data, true);
270 		if (ret)
271 			return ret;
272 		mutex_lock(&data->lock);
273 		ret = ltrf216a_read_data(data, LTRF216A_ALS_DATA_0);
274 		mutex_unlock(&data->lock);
275 		ltrf216a_set_power_state(data, false);
276 		if (ret < 0)
277 			return ret;
278 		*val = ret;
279 		return IIO_VAL_INT;
280 	case IIO_CHAN_INFO_PROCESSED:
281 		mutex_lock(&data->lock);
282 		ret = ltrf216a_get_lux(data);
283 		mutex_unlock(&data->lock);
284 		if (ret < 0)
285 			return ret;
286 		*val = ret;
287 		*val2 = data->als_gain_fac * data->int_time_fac;
288 		return IIO_VAL_FRACTIONAL;
289 	case IIO_CHAN_INFO_INT_TIME:
290 		mutex_lock(&data->lock);
291 		ret = ltrf216a_get_int_time(data, val, val2);
292 		mutex_unlock(&data->lock);
293 		return ret;
294 	default:
295 		return -EINVAL;
296 	}
297 }
298 
299 static int ltrf216a_write_raw(struct iio_dev *indio_dev,
300 			      struct iio_chan_spec const *chan, int val,
301 			      int val2, long mask)
302 {
303 	struct ltrf216a_data *data = iio_priv(indio_dev);
304 	int ret;
305 
306 	switch (mask) {
307 	case IIO_CHAN_INFO_INT_TIME:
308 		if (val != 0)
309 			return -EINVAL;
310 		mutex_lock(&data->lock);
311 		ret = ltrf216a_set_int_time(data, val2);
312 		mutex_unlock(&data->lock);
313 		return ret;
314 	default:
315 		return -EINVAL;
316 	}
317 }
318 
319 static int ltrf216a_read_available(struct iio_dev *indio_dev,
320 				   struct iio_chan_spec const *chan,
321 				   const int **vals, int *type, int *length,
322 				   long mask)
323 {
324 	switch (mask) {
325 	case IIO_CHAN_INFO_INT_TIME:
326 		*length = ARRAY_SIZE(ltrf216a_int_time_available) * 2;
327 		*vals = (const int *)ltrf216a_int_time_available;
328 		*type = IIO_VAL_INT_PLUS_MICRO;
329 		return IIO_AVAIL_LIST;
330 	default:
331 		return -EINVAL;
332 	}
333 }
334 
335 static const struct iio_info ltrf216a_info = {
336 	.read_raw = ltrf216a_read_raw,
337 	.write_raw = ltrf216a_write_raw,
338 	.read_avail = ltrf216a_read_available,
339 };
340 
341 static bool ltrf216a_readable_reg(struct device *dev, unsigned int reg)
342 {
343 	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
344 	struct ltrf216a_data *data = iio_priv(indio_dev);
345 
346 	switch (reg) {
347 	case LTRF216A_MAIN_CTRL:
348 	case LTRF216A_ALS_MEAS_RES:
349 	case LTRF216A_ALS_GAIN:
350 	case LTRF216A_PART_ID:
351 	case LTRF216A_MAIN_STATUS:
352 	case LTRF216A_ALS_DATA_0:
353 	case LTRF216A_ALS_DATA_1:
354 	case LTRF216A_ALS_DATA_2:
355 	case LTRF216A_INT_CFG:
356 	case LTRF216A_INT_PST:
357 	case LTRF216A_ALS_THRES_UP_0:
358 	case LTRF216A_ALS_THRES_UP_1:
359 	case LTRF216A_ALS_THRES_UP_2:
360 	case LTRF216A_ALS_THRES_LOW_0:
361 	case LTRF216A_ALS_THRES_LOW_1:
362 	case LTRF216A_ALS_THRES_LOW_2:
363 		return true;
364 	case LTRF216A_ALS_CLEAR_DATA_0:
365 	case LTRF216A_ALS_CLEAR_DATA_1:
366 	case LTRF216A_ALS_CLEAR_DATA_2:
367 		return data->info->has_clear_data;
368 	default:
369 		return false;
370 	}
371 }
372 
373 static bool ltrf216a_writable_reg(struct device *dev, unsigned int reg)
374 {
375 	switch (reg) {
376 	case LTRF216A_MAIN_CTRL:
377 	case LTRF216A_ALS_MEAS_RES:
378 	case LTRF216A_ALS_GAIN:
379 	case LTRF216A_INT_CFG:
380 	case LTRF216A_INT_PST:
381 	case LTRF216A_ALS_THRES_UP_0:
382 	case LTRF216A_ALS_THRES_UP_1:
383 	case LTRF216A_ALS_THRES_UP_2:
384 	case LTRF216A_ALS_THRES_LOW_0:
385 	case LTRF216A_ALS_THRES_LOW_1:
386 	case LTRF216A_ALS_THRES_LOW_2:
387 		return true;
388 	default:
389 		return false;
390 	}
391 }
392 
393 static bool ltrf216a_volatile_reg(struct device *dev, unsigned int reg)
394 {
395 	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
396 	struct ltrf216a_data *data = iio_priv(indio_dev);
397 
398 	switch (reg) {
399 	case LTRF216A_MAIN_STATUS:
400 	case LTRF216A_ALS_DATA_0:
401 	case LTRF216A_ALS_DATA_1:
402 	case LTRF216A_ALS_DATA_2:
403 		return true;
404 	/*
405 	 * If these registers are not present on a chip (like LTR-308),
406 	 * the missing registers are not considered volatile.
407 	 */
408 	case LTRF216A_ALS_CLEAR_DATA_0:
409 	case LTRF216A_ALS_CLEAR_DATA_1:
410 	case LTRF216A_ALS_CLEAR_DATA_2:
411 		return data->info->has_clear_data;
412 	default:
413 		return false;
414 	}
415 }
416 
417 static bool ltrf216a_precious_reg(struct device *dev, unsigned int reg)
418 {
419 	return reg == LTRF216A_MAIN_STATUS;
420 }
421 
422 static const struct regmap_config ltrf216a_regmap_config = {
423 	.name = "ltrf216a",
424 	.reg_bits = 8,
425 	.val_bits = 8,
426 	.cache_type = REGCACHE_RBTREE,
427 	.max_register = LTRF216A_ALS_THRES_LOW_2,
428 	.readable_reg = ltrf216a_readable_reg,
429 	.writeable_reg = ltrf216a_writable_reg,
430 	.volatile_reg = ltrf216a_volatile_reg,
431 	.precious_reg = ltrf216a_precious_reg,
432 	.disable_locking = true,
433 };
434 
435 static int ltrf216a_probe(struct i2c_client *client)
436 {
437 	struct ltrf216a_data *data;
438 	struct iio_dev *indio_dev;
439 	int ret;
440 
441 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
442 	if (!indio_dev)
443 		return -ENOMEM;
444 
445 	data = iio_priv(indio_dev);
446 
447 	data->regmap = devm_regmap_init_i2c(client, &ltrf216a_regmap_config);
448 	if (IS_ERR(data->regmap))
449 		return dev_err_probe(&client->dev, PTR_ERR(data->regmap),
450 				     "regmap initialization failed\n");
451 
452 	i2c_set_clientdata(client, indio_dev);
453 	data->client = client;
454 	data->info = i2c_get_match_data(client);
455 
456 	mutex_init(&data->lock);
457 
458 	indio_dev->info = &ltrf216a_info;
459 	indio_dev->name = "ltrf216a";
460 	indio_dev->channels = ltrf216a_channels;
461 	indio_dev->num_channels = ARRAY_SIZE(ltrf216a_channels);
462 	indio_dev->modes = INDIO_DIRECT_MODE;
463 
464 	ret = pm_runtime_set_active(&client->dev);
465 	if (ret)
466 		return ret;
467 
468 	/* reset sensor, chip fails to respond to this, so ignore any errors */
469 	ltrf216a_reset(indio_dev);
470 
471 	ret = regmap_reinit_cache(data->regmap, &ltrf216a_regmap_config);
472 	if (ret)
473 		return dev_err_probe(&client->dev, ret,
474 				     "failed to reinit regmap cache\n");
475 
476 	ret = ltrf216a_enable(indio_dev);
477 	if (ret)
478 		return ret;
479 
480 	ret = devm_add_action_or_reset(&client->dev, ltrf216a_cleanup,
481 				       indio_dev);
482 	if (ret)
483 		return ret;
484 
485 	ret = devm_pm_runtime_enable(&client->dev);
486 	if (ret)
487 		return dev_err_probe(&client->dev, ret,
488 				     "failed to enable runtime PM\n");
489 
490 	pm_runtime_set_autosuspend_delay(&client->dev, 1000);
491 	pm_runtime_use_autosuspend(&client->dev);
492 
493 	data->int_time = 100000;
494 	data->int_time_fac = 100;
495 	data->als_gain_fac = 3;
496 
497 	return devm_iio_device_register(&client->dev, indio_dev);
498 }
499 
500 static int ltrf216a_runtime_suspend(struct device *dev)
501 {
502 	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
503 	struct ltrf216a_data *data = iio_priv(indio_dev);
504 	int ret;
505 
506 	ret = ltrf216a_disable(indio_dev);
507 	if (ret)
508 		return ret;
509 
510 	regcache_cache_only(data->regmap, true);
511 
512 	return 0;
513 }
514 
515 static int ltrf216a_runtime_resume(struct device *dev)
516 {
517 	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
518 	struct ltrf216a_data *data = iio_priv(indio_dev);
519 	int ret;
520 
521 	regcache_cache_only(data->regmap, false);
522 	regcache_mark_dirty(data->regmap);
523 	ret = regcache_sync(data->regmap);
524 	if (ret)
525 		goto cache_only;
526 
527 	ret = ltrf216a_enable(indio_dev);
528 	if (ret)
529 		goto cache_only;
530 
531 	return 0;
532 
533 cache_only:
534 	regcache_cache_only(data->regmap, true);
535 
536 	return ret;
537 }
538 
539 static DEFINE_RUNTIME_DEV_PM_OPS(ltrf216a_pm_ops, ltrf216a_runtime_suspend,
540 				 ltrf216a_runtime_resume, NULL);
541 
542 static const struct ltr_chip_info ltr308_chip_info = {
543 	.has_clear_data		= false,
544 	.lux_multiplier		= 60,
545 };
546 
547 static const struct ltr_chip_info ltrf216a_chip_info = {
548 	.has_clear_data		= true,
549 	.lux_multiplier		= 45,
550 };
551 
552 static const struct i2c_device_id ltrf216a_id[] = {
553 	{ .name = "ltr308", .driver_data = (kernel_ulong_t)&ltr308_chip_info },
554 	{ .name = "ltrf216a", .driver_data = (kernel_ulong_t)&ltrf216a_chip_info },
555 	{ }
556 };
557 MODULE_DEVICE_TABLE(i2c, ltrf216a_id);
558 
559 static const struct of_device_id ltrf216a_of_match[] = {
560 	{ .compatible = "liteon,ltr308", .data = &ltr308_chip_info },
561 	{ .compatible = "liteon,ltrf216a", .data = &ltrf216a_chip_info },
562 	/* For Valve's Steamdeck device, an ACPI platform using PRP0001 */
563 	{ .compatible = "ltr,ltrf216a", .data = &ltrf216a_chip_info },
564 	{ }
565 };
566 MODULE_DEVICE_TABLE(of, ltrf216a_of_match);
567 
568 static struct i2c_driver ltrf216a_driver = {
569 	.driver = {
570 		.name = "ltrf216a",
571 		.pm = pm_ptr(&ltrf216a_pm_ops),
572 		.of_match_table = ltrf216a_of_match,
573 	},
574 	.probe = ltrf216a_probe,
575 	.id_table = ltrf216a_id,
576 };
577 module_i2c_driver(ltrf216a_driver);
578 
579 MODULE_AUTHOR("Shreeya Patel <shreeya.patel@collabora.com>");
580 MODULE_AUTHOR("Shi Zhigang <Zhigang.Shi@liteon.com>");
581 MODULE_DESCRIPTION("LTRF216A ambient light sensor driver");
582 MODULE_LICENSE("GPL");
583